Jim @ EuroWerks

I have always seen LH controllers fail 1st by not powering the fuel pump relay. Then 2nd by not powering the injectors. "WE," in the shop have just reinstalled an intake and valve covers on a 87 S4. Now when turning the switch on (not starting) the injectors fire wildly like a frequency valve. Anyone ever seen this?

Randy V

Sounds like a typical LH controller failure, Jim.

Jim bailey - 928 International

Unfortunately YES it is becoming much more common for them to trigger continuously

Jim @ EuroWerks

Jim is sad

Gregg K

There's a guy who repairs them in Germany. If that's an option. I don't know if it's ok to post his email, but I've got contact info.

It's sad, and you've been such a nice guy. Just isn't fair.

Steve J.

No fuel pump and injectors firing without the engine running were the symptoms when my ECU failed. By jumping the fuel pump and feathering the throttle to sync with the injector firing rate, I was able to keep the engine running at a specific rpm and limp home. Tricky with an automatic. Would be very difficult with a 5spd. Seems like '87's ecu's are especially failure prone for some reason. Partwerks repaired (actually exchanged) mine and it still works after almost 2 years. I will probably give John Speake a try if it ever happens again - good reviews about his work.

Jim @ EuroWerks

Thanks Guys I've never seen one fail like this.

ErnestSw

Jim Speake, a Rennlist sponsor, who offers EXCELLENT service at a very reasonable price, can repair most LH brains and, I think, has a representative in the US who can offer a quick turnaround time.

Tony

thats how mine failed. Walked into the grocery store, 15 miuntes later walked out and turned the key...tick tick tick tick tick tick..
NADA.

bummer

John Speake

Jim,
If this has occurred after you did some work on the car, its worth checking the ground point on the block, under the lower engine airfilter cover. The same bolt hold the cleat for one of the knock sensor leads.

If that ground goes open, then you can get all sorts of wierd results.

I have sent you a PM if the worst has happened...............

Jfrahm

What can we do to prevent this?

Check the grounds?
Add extra ground wires?
Turn the parking lights on when (dis)connecting the battery?

I would love to add some cooling to the factory ECU but I have not figured out a good way to do this. A few feet of that wonderful heat pipe they use for laptop CPU's would be great.

Thanks,
-Joel.

Steve J.

Since the glove box is air conditioned, maybe a cooling duct could be routed from the glove box to the ecu.

T Colvin

Hi to one and all,
I'm a new owner of an 84 928s Auto, had it for about a month now. The car does not run, but I'm trying. I have been reading all your thread for a while now, but to much of a chicken to participate. I have a problem and I need higher knowledge to resolve it. I believe I have narrow it down to the injectors. Is it possible for all the injectors to go bad if the car was park for about a year? The car will crank over. The spark is there. And I believe the fuel pressure is good, but have not check it with a gauge. I pull the injectors and try to start up the car, but no gas from the injectors. I thought the brain was dead, but Susan from Devek tested the brain and it's good. What could stop the injectors from working? Please help, I want to go to Sharktoberfest with my shark and not my wife's car.

ViribusUnits

You my freind, I can probably help. We are fortunate, because we both have the same EFI system.

The odds of ALL the injectors going bad are pretty much slim to none.

The most likely item is the relay that provides power to the EFI system. Go to www.928gt.com Get fimiler with the site, and they're some nice folks that know alought about the 928. (and devek.net, and 928intl.com) Anyways, 928gt.com has a section that has the fuse and relay charts for your car. Down load, put in glove box for your road side use.

OK, all the relays are in the passangers foot well, as I'm sure you know. Pull the relay in the socket number XVI. This is the relay for the fuel injector system. It provides power to both the injectors, and the brain on my car, and probably your car too. (83s are suppost to be realy similer to 84s) Unfortuanly, the relay doesn't match part numbers with any of the other relays. My suggestion is to make a bridge, between terminal 30, and BOTH terminals 87, IIRC. IIRC, you have to bridge to both 87s to provide power to the injectors, and the brain.

Another possibility is that the fuel pump relay is bad. To check, build a jumper from terminal 30 to terminal 87. If the fuel pump runs, and the car starts like this, but not with the relay, you probably need a new relay. Also, check fuse 22. looking it's good enough. You pretty much need to pull it out, clean it up, clean the socket up, and then put it back in.

If eighter of the two relays turn out bad, you need to buy the specific relay. Not just general ones. It's also a good idea to keep a few spares in the car, cause they can go out in a heart beat.

Finaly, there could be a bad ground, or connection somewhere in the system. The EFI system is grounded in at least 4 places. These include, IIRC, as I'm away from my books, the two on the frount lock member, one on the intake mannafold, the one in the rear passangers side of the hatchback area.

T Colvin

Viribus,

Thanks for the lead. The brain unit should be back from Devek today and I will test it again. Oh oh oh, something had just occur to me. Do I need to try and start the car while I'm bridging the relay. I have not done that and logically thinking I need to or how else the car will start. thank ya, thank ya, thank ya.